Inbred corn line MNI1

ABSTRACT

An inbred corn line, designated MNI1, is disclosed. The invention relates to the seeds of inbred corn line MNI1, to the plants of inbred corn line MNI1 and to methods for producing a corn plant produced by crossing the inbred line MNI1 with itself or another corn line.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinctive corn inbred line,designated MNI1. There are numerous steps in the development of anynovel, desirable plant germplasm. Plant breeding begins with theanalysis and definition of problems and weaknesses of the currentgermplasm, the establishment of program goals, and the definition ofspecific breeding objectives. The next step is selection of germplasmthat possess the traits to meet the program goals. The goal is tocombine in a single variety or hybrid an improved combination ofdesirable traits from the parental germplasm. These important traits mayinclude higher yield, resistance to diseases and insects, better stalksand roots, tolerance to drought and heat, reduction of the time to cropmaturity and better agronomic quality. With mechanical harvesting ofmany crop, uniformity of plant characteristics such as germination andstand establishment, growth rate, maturity and plant and ear height isimportant.

Choice of breeding or selection methods depends on the mode of plantreproduction, the heritability of the trait(s) being improved, and thetype of cultivar used commercially (e.g., F.sub.1 hybrid cultivar,pureline cultivar, etc.). For highly heritable traits, a choice ofsuperior individual plants evaluated at a single location will beeffective, whereas for traits with low heritability, selection should bebased on mean values obtained from replicated evaluations of families ofrelated plants. Popular selection methods commonly include pedigreeselection, modified pedigree selection, mass selection, and recurrentselection.

The complexity of inheritance influences choice of the breeding method.Backcross breeding is used to transfer one or a few favorable genes fora highly heritable trait into a desirable cultivar. This approach hasbeen used extensively for breeding disease-resistant cultivars. Variousrecurrent selection techniques are used to improve quantitativelyinherited traits controlled by numerous genes. The use of recurrentselection in self-pollinating crops depends on the ease of pollination,the frequency of successful hybrids from each pollination, and thenumber of hybrid offspring from each successful cross.

Each breeding program should include a periodic, objective evaluation ofthe efficiency of the breeding procedure. Evaluation criteria varydepending on the goal and objectives, but should include gain fromselection per year based on comparisons to an appropriate standard,overall value of the advanced breeding lines, and number of successfulcultivars produced per unit of input (e.g., per year, per dollarexpended, etc.).

Promising advanced breeding lines are thoroughly tested and compared toappropriate standards in environments representative of the commercialtarget area(s) for three years at least. The best lines are candidatesfor new commercial cultivars; those elite in traits are used as parentsto produce new populations for further selection.

These processes, which lead to the final step of marketing anddistribution, usually take from eight to twelve years from the time thefirst cross is made. Therefore, development of new cultivars is atime-consuming process that requires precise forward planning, efficientuse of resources, and a minimum of changes in direction.

A most difficult task is the identification of individuals that aregenetically superior, because for most traits the true genotypic valueis masked by other confounding plant traits or environmental factors.One method of identifying a superior plant is to observe its performancerelative to other experimental plants and to a widely grown standardcultivar. If a single observation is inconclusive, replicatedobservations provide a better estimate of its genetic worth.

The goal of plant breeding is to develop new, unique and superior corninbred lines and hybrids. The breeder initially selects and crosses twoor more parental lines, followed by repeated selfing and selection,producing many new genetic combinations. The breeder can theoreticallygenerate billions of different genetic combinations via crossing,selfing and mutations. The breeder has no direct control at the cellularlevel. Therefore, two breeders will never develop the same line, or evenvery similar lines, having the same corn traits.

Each year, the plant breeder selects the germplasm to advance to thenext generation. This germplasm is grown under unique and differentgeographical, climatic and soil conditions, and further selections arethen made, during and at the end of the growing season. The inbred lineswhich are developed are unpredictable. This unpredictability is becausethe breeder's selection occurs in unique environments, with no controlat the DNA level (using conventional breeding procedures), and withmillions of different possible genetic combinations being generated. Abreeder of ordinary skill in the art cannot predict the final resultinglines he develops, except possibly in a very gross and general fashion.The same breeder cannot produce the same line twice by using the exactsame original parents and the same selection techniques. Thisunpredictability results in the expenditure of large research monies todevelop a superior new corn inbred line.

The development of commercial corn hybrids requires the development ofhomozygous inbred lines, the crossing of these lines, and the evaluationof the crosses. Pedigree breeding and recurrent selection breedingmethods are used to develop inbred lines from breeding populations.Breeding programs combine desirable traits from two or more inbred linesor various broad-based sources into breeding pools from which inbredlines are developed by selfing and selection of desired phenotypes. Thenew inbreds are crossed with other inbred lines and the hybrids fromthese crosses are evaluated to determine which have commercialpotential.

Pedigree breeding is used commonly for the improvement ofself-pollinating crops or inbred lines of cross-pollinating crops. Twoparents which possess favorable, complementary traits are crossed toproduce an F₁. An F₂ population is produced by selfing one or severalF₁'s or by intercrossing two F₁'s (sib mating). Selection of the bestindividuals is usually begun in the F₂ population; then, beginning inthe F₃, the best individuals in the best families are selected.Replicated testing of families, or hybrid combinations involvingindividuals of these families, often follows in the F₄ generation toimprove the effectiveness of selection for traits with low heritability.At an advanced stage of inbreeding (i.e., F₆ and F₇), the best lines ormixtures of phenotypically similar lines are tested for potentialrelease as new cultivars.

Mass and recurrent selections can be used to improve populations ofeither self- or cross-pollinating crops. A genetically variablepopulation of heterozygous individuals is either identified or createdby intercrossing several different parents. The best plants are selectedbased on individual superiority, outstanding progeny, or excellentcombining ability. The selected plants are intercrossed to produce a newpopulation in which further cycles of selection are continued.

Backcross breeding has been used to transfer genes for a simplyinherited, highly heritable trait into a desirable homozygous cultivaror inbred line which is the recurrent parent. The source of the trait tobe transferred is called the donor parent. After the initial cross,individuals possessing the phenotype of the donor parent are selectedand repeatedly crossed (backcrossed) to the recurrent parent. Theresulting plant is expected to have the attributes of the recurrentparent (e.g., cultivar) and the desirable trait transferred from thedonor parent.

Descriptions of other breeding methods that are commonly used fordifferent traits and crops can be found in one of several referencebooks (e.g., Allard, R. W. “Principles of Plant Breeding” John Wiley andSon, pp.115-161, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987).

Proper testing should detect any major faults and establish the level ofsuperiority or improvement over current cultivars. In addition toshowing superior performance, there must be a demand for a new cultivarthat is compatible with industry standards or which creates a newmarket. The introduction of a new cultivar will incur additional coststo the seed producer, the grower, processor and consumer; for specialadvertising and marketing, altered seed and commercial productionpractices, and new product utilization. The testing preceding release ofa new cultivar should take into consideration research and developmentcosts as well as technical superiority of the final cultivar. Forseed-propagated cultivars, it must be feasible to produce seed easilyand economically.

Once the inbreds that give the best hybrid performance have beenidentified, the hybrid seed can be reproduced indefinitely as long asthe homogeneity of the inbred parent is maintained. A single-crosshybrid is produced when two inbred lines are crossed to produce the F₁progeny. A double-cross hybrid is produced from four inbred linescrossed in pairs (A×B and C×D) and then the two F₁ hybrids are crossedagain (A×B)×(C×D). Much of the hybrid vigor exhibited by F₁ hybrids islost in the next generation. Consequently, seed from hybrid varieties isnot used for planting stock.

Hybrid maize seed is typically produced by manual or mechanicaldetasseling. Alternate strips of two maize inbreds are planted in afield, and the pollen-bearing tassels are removed from one of theinbreds (female). Providing that there is sufficient isolation fromsources of foreign maize pollen, the ears of the detasseled inbred willbe fertilized only from the other inbred (male), and the resulting seedis therefore hybrid and will form hybrid plants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent inmaize plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511, allpatents referred to being incorporated by reference.

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach.

Corn is an important and valuable field crop. Thus, a continuing goal ofplant breeders is to develop stable, high yielding corn hybrids that areagronomically sound. The reasons for this goal are obviously to maximizethe amount of grain produced on the land used and to supply food forboth animals and humans. To accomplish this goal, the corn breeder mustselect and develop corn plants that have the traits that result insuperior parental lines for producing hybrids.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line,designated MNI1. This invention thus relates to the seeds of inbred cornline MNI1, to the plants of inbred corn line MNI1 and to methods forproducing a corn plant produced by crossing the inbred line MNI1 withitself or another corn line. This invention further relates to hybridcorn seeds and plants produced by crossing the inbred line MNI1 withanother corn line.

The inbred corn plant of the invention may further comprise, or have, acytoplasmic factor, or other factor, that is capable of conferring malesterility. So, the invention further comprises a male sterile form ofthe inbred. Parts of the corn plant of the present invention are alsoprovided, such as e.g., pollen obtained from an inbred plant and anovule of the inbred plant.

In one aspect, the present invention provides regenerable cells for usein tissue culture or inbred corn plant MNI1. The tissue culture willpreferably be capable of regenerating plants having the physiologicaland morphological characteristics of the foregoing inbred corn plant,and of regenerating plants having substantially the same genotype as theforegoing inbred corn plant. Preferably, the regenerable cells in suchtissue cultures will be embryos, protoplasts, meristematics cells,callus, pollen, leaves, anthers, roots, root tips, silk, kernels, ears,cobs, husk or stalks. Still further, the present invention provides cornplant regenerated from the tissue cultures of the invention.

Another objective of the invention is to provide methods for producingother inbred corn plants derived from inbred corn line MNI1. Inbred cornlines derived by the use of those methods are also part of theinvention.

The invention also relates to methods for producing a corn plantcontaining in its genetic material one or more transgenes and to thetransgenic corn plant produced by that method.

In another aspect, the present invention provides for single geneconverted plants of MNI1. The single transferred gene may preferably bea dominant or recessive allele. Preferably, the single transferred genewill confer such trait as male sterility, herbicide resistance, insectresistance, resistance for bacterial, fungal, or viral disease, malefertility, enhanced nutritional quality, and industrial usage. Thesingle gene may be a naturally occurring maize gene or a transgeneintroduced through genetic engineering techniques.

The invention further provides methods for developing corn plant in acorn plant breeding program using plant breeding technique includingrecurrent selection, backcrossing, pedigree breeding, restrictionfragment length polymorphism enhanced selection, genetic marker enhancedselection and transformation. Seeds, corn plant, and parties thereofproduced by such breeding methods are also part of the invention.

Definitions

In the description and tables which follow, a number of terms are used.In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

Allele. The allele is any of one or more alternative form of a gene, allof which alleles relates to one trait or characteristic. In a diploidcell or organism, the two alleles of a given gene occupy correspondingloci on a pair of homologous chromosomes.

Backcrossing. Backcrossing is a process in which a breeder repeatedlycrosses hybrid progeny back to one of the parents, for example, a firstgeneration hybrid F₁ with one of the parental genotype of the F₁ hybrid.

Essentially all the physiological and morphological characteristics. Aplant having essentially all the physiological and morphologicalcharacteristics means a plant having the physiological and morphologicalcharacteristics, except for the characteristics derived from theconverted gene.

Regeneration. Regeneration refers to the development of a plant fromtissue culture.

Single gene converted. Single gene converted or conversion plant refersto plants which are developed by a plant breeding technique calledbackcrossing wherein essentially all of the desired morphological andphysiological characteristics of an inbred are recovered in addition tothe single gene transferred into the inbred via the backcrossingtechnique or via genetic engineering.

Predicted RM. This trait for a hybrid, predicted relative maturity (RM),is based on the harvest moisture of the grain. The relative maturityrating is based on a known set of checks and utilizes conventionalmaturity such as the Comparative Relative Maturity Rating System or itssimilar, the Minnesota Relative Maturity Rating System.

MN RM. This represents the Minnesota Relative Maturity Rating (MN RM)for the hybrid and is based on the harvest moisture of the grainrelative to a standard set of checks of previously determined MN RMrating. Regression analysis is used to compute this rating.

Yield (Bushels/Acre). The yield in bushels/acre is the actual yield ofthe grain at harvest adjusted to 15.5% moisture.

Moisture. The moisture is the actual percentage moisture of the grain atharvest.

GDU Silk. The GDU silk (=heat unit silk) is the number of growing degreeunits (GDU) or heat units required for an inbred line or hybrid to reachsilk emergence from the time of planting. Growing degree units arecalculated by the Barger Method, where the heat units for a 24-hourperiod are: GDU=((Max Temp+Min Temp)/2)−50 The highest maximum used is86° F. and the lowest minimum used is 50° F. For each hybrid, it takes acertain number of GDUs to reach various stages of plant development.GDUs are a way of measuring plant maturity.

Stalk Lodging. This is the percentage of plants that stalk lodge, i.e.,stalk breakage, as measured by either natural lodging or pushing thestalks determining the percentage of plants that break off below theear. This is a relative rating of a hybrid to other hybrids forstandability.

Root Lodging. The root lodging is the percentage of plants that rootlodge; i.e., those that lean from the vertical axis at an approximate30° angle or greater would be counted as root lodged.

Plant Height. This is a measure of the height of the hybrid from theground to the tip of the tassel, and is measured in centimeters.

Ear Height. The ear height is a measure from the ground to the ear nodeattachment, and is measured in centimeters.

Dropped Ears. This is a measure of the number of dropped ears per plot,and represents the percentage of plants that dropped an ear prior toharvest.

Stay Green. Stay green is the measure of plant health near the time ofblack layer formation (physiological maturity). A high score indicatesbetter late-season plant health.

DETAILED DESCRIPTION OF THE INVENTION

Inbred corn line MNI1 is a yellow dent corn with superiorcharacteristics, and provides an excellent parental line in crosses forproducing first generation (F₁) hybrid corn. Inbred corn line MNI1 isbest adapted to the Central corn belt, Northcentral, Southwest andWestern regions of the USA and can be used to produce hybrids having arelative maturity of approximately 107 on the Comparative RelativeMaturity Rating System for harvest moisture of grain. Inbred corn lineMNI1 shows an excellent seedling vigor, an early pollen shed, excellentbrittle stalk resistance, excellent husk cover and above average staygreen.

MNI1 is similar to LH123, however there are numerous differencesincluding the fact that MNI1 flowers substantially earlier than LH123.Hybrids with MNI1 also are lower eared and have a stronger smuttolerance.

MNI1 has a plant height of 245 cm with an average ear insertion of 62cm. The kernels are arranged in distinct and slightly curved rows on theear. Heat units to 50% pollen shed are approximately 1450 and to 50%silk are approximately 1491.

MNI1 is an inbred line with very high yield potential and very strongstalk and roots in hybrids. For an inbred of its maturity, MNI1 resultsin a lower ear position in hybrid combination. Often these hybridscombinations results in plants which are of much better than averageoverall health when compared to inbred lines of similar maturity.

Some of the criteria used to select ears in various generations include:yield, stalk quality, root quality, disease tolerance, late plantgreenness, late season plant intactness, ear retention, ear height,pollen shedding ability, silking ability, and corn borer tolerance.During the development of the line, crosses were made to inbred testersfor the purpose of estimating the line's general and specific combiningability, and parallel evaluations were run in France and in the USA bythe Champaign, Ill. Research Station. The inbred was evaluated furtheras a line and in numerous crosses by the Champaign station and otherresearch stations across the Corn Belt. The inbred has proven to have agood combining ability in hybrid combinations.

The inbred line has shown uniformity and stability for the traits, asdescribed in the following variety description information. It has beenself-pollinated a sufficient number of generations with carefulattention to uniformity of plant type. The line has been increased withcontinued observation for uniformity. No variant traits have beenobserved or are expected in MNI1.

Inbred corn line MNI1 has the following morphologic and othercharacteristics (based primarily on data collected at Kirkland, Ill. andChampaign, Ill).

TABLES 1 VARIETY DESCRIPTION INFORMATION  1. TYPE: Dent  2. REGION WHEREDEVELOPED: France.  3. MATURITY: Days Heat Units From emergence to 50%of plants 64 1491 in silk: From emergence to 50% of plants 62.5 1450 inpollen: Heat Units: = GDU = ((Max Temp + Min Temp)/2) − 50  4. PLANT:Plant Height to tassel tip: 244.45 cm (Standard Deviation =    8.44) EarHeight to base of top ear: 61.95 cm  (4.79) Average Length of Top Ear17.26 cm  (0.67) Internode: Average number of Tillers: 0  (0) AverageNumber of Ears per Stalk: 1  (0) Anthocyanin of Brace Roots: moderate 5. LEAF: Width of Ear Node Leaf: 9.6 cm  (0.40) Length of Ear NodeLeaf: 85.39 cm  (2.70) Number of leaves above top ear: 5.75  (0.45) LeafAngle (from 2nd Leaf above 68.55°  (3.08) ear at anthesis to Stalk aboveleaf): Leaf Color: Dark Green Munsell Code 5GY 4/4 Leaf SheathPubescence 4 (Rate on scale from 1 = none to 9 = like peach fuzz):Marginal Waves 5 (Rate on scale from 1 = none to 9 = many): LongitudinalCreases 6.5 (Rate on scale from 1 = none to 9 = many):  6. TASSEL:Number of Lateral Branches: 8.05  (1.07) Branch Angle from CentralSpike: 51.55  (5.37) Tassel Length (from top leaf 47.9 cm  (2.24) collarto tassel top): Pollen Shed 6.5 (Rate on scale from 0 = male sterile to9 = heavy shed): Anther Color: Light Green Munsell Code 2.5GY 8/4 GlumeColor: Light Green Munsell Code 5GY 7/6 Bar Glumes: absent  7a. EAR:(Unhusked Data) Silk Color (3 days after emergence): Light green MunsellCode 2.5GY 8/6 Fresh Husk Color (25 days after 50% silking): Light GreenMunsell Code 5GY 7/8 Dry Husk Color (65 days after 50% silking): LightGreen Munsell Code 2.5GY 8/6 Position of Ear: upright Husk Tightness 1(Rate on scale from 1 = very loose to 9 = very tight): Husk Extension atharvest: short (ear exposed)  7b. EAR: (Husked Ear Data) Ear Length:14.65 cm  (1.01) Ear Diameter at mid-point: 40.22 mm  (1.25) Ear Weight:90.1 gm (12.44) Number of Kernel Rows: 15.7  (1.53) Kernel Rows:distinct Row Alignment: slightly curved Shank Length: 8.73 cm  (1.73)Ear Taper: average  8. KERNEL: (Dried) Kernel Length: 9.87 mm  (0.40)Kernel Width: 7.64 mm  (0.66) Kernel Thickness: 5.58 mm  (0.82) RoundKernels (Shape Grade): 76.46%  (9.36) Aleurone Color Pattern: homozygousAleurone Color: colorless Hard Endosperm Color: yellow (Munsell code2.5Y 8/12) Endosperm Type: normal starch Weight per 100 kernels 26.35 gm (2.00) (unsized sample):  9. COB: Cob Diameter at Mid-Point: 26.21 mm (1.01) Cob Color: Red Munsell code 2.5YR 5/6 10. AGRONOMIC TRAITS: StayGreen 7 (at 65 days after anthesis) (Rate on scale from 1 = worst to 9 =excellent) 0% Dropped Ears (at 65 days after anthesis) 0% Pre-anthesisBrittle Snapping 0% Pre-anthesis Root Lodging 0% Post-anthesis RootLodging (at 65 days after anthesis) Yield of Inbred Per Se 32.5 Bu/ (at12-13% grain moisture): Acre

TABLES

In the tables that follow, the traits and characteristics of inbred cornline MNI1 are given in hybrid combination. The data collected on inbredcorn line MNI1 is presented for the key characteristics and traits. Thetables present yield test information about MNI1. MNI1 was tested inseveral hybrid combinations at numerous locations, with two or threereplications per location. Information about these hybrids, as comparedto several check hybrids, is presented.

The first pedigree listed in the comparison group is the hybridcontaining MNI1. Information for each pedigree includes:

1. Mean yield in Qx/Ha of the hybrid across all locations (Mean Yield)is shown in column 2.

2. A mean for the percentage moisture (% Moist) for the hybrid acrossall locations is shown in column 3.

3. A mean of the percentage of plants with stalk lodging (% Stalk)across all locations is shown in column 4.

4. A mean of the percentage of plants with root lodging (% Root) acrossall locations is shown in column 5.

5. A note on the stay green across all location from 1 (poor) to 9(good) is shown in column 6.

6. A mean of the percentage of plants with head smut (% head smut)across all locations is shown in column 7.

7. Test weight is the grain density measured in kg per 100 l is shown incolumn 8.

8. A mean of plant height in cm is shown in column 9.

TABLE 2 Overall Comparisons Hybrid vs. Check Hybrids Location: South ofFrance, 1998 Mean Stay % Head Test Plant Pedigree Yield % Moist % Stalk% Root Green Smut Weight Height FR1064*MNI1 121.6 31.3 3 8 3 65.9 270MNI1*SBB1 118.0 30.1 4 7 2 61.7 280 LH227*MNI1 118.2 29.4 8 6 2 66.2 280MNI1*SGI742 121.5 30.5 5 7 5 63.7 255 At 14 Locations As Compared to:P3514 110.1 29.2 4 6 1 63 258 P3394 119.6 29.6 4 8 6 65.5 272 DK604117.4 29.7 5 8 1 61.4 268 LG2447 106.0 27.1 5 6 19  65.8 245 P3527 120.629.4 3 8 1 65.8 275

TABLE 3 Overall Comparisons Hybrid vs. Check Hybrids Location: South ofFrance, 1999 Mean Stay % Head Test Plant Pedigree Yield % Moist % Stalk% Root Green Smut Weight Height FR1064*MNI1 115.5 29.5 7 2 8 4 70.1 276MNI1*SBB1 120.3 27.4 7 3 7 4 68 285 LH227*MNI1 113.2 27.4 11  4 8 1 70284 MNI1*SGI742 116.3 28.5 8 2 7 4 69 286 At 15 Locations As Comparedto: P3514  99.8 27.5 8 5 6 1 69 236 P34B15 117.7 27.4 7 3 7 3 71.2 289P3394 111.4 27.2 11  8 7 4 69.8 258 DK604 116.1 26.9 8 8 7 3 67.7 275LG2447 107.7 24.7 7 1 5 39  70.9 260 P3527 112.3 27.1 10  8 7 11  69.7269

FURTHER EMBODIMENTS OF THE INVENTION

This invention is also directed to methods for producing a corn plant bycrossing a first parent corn plant with a second parent corn plant,wherein the first or second corn plant is the inbred corn plant from theline MNI1. Further, both first and second parent corn plants may be fromthe inbred line MNI1. Therefore, any methods using the inbred corn lineMNI1 are part of this invention: selfing, backcrosses, hybrid breeding,and crosses to populations. Any plants produced using inbred corn lineMNI1 as a parent are within the scope of this invention. Advantageously,the inbred corn line is used in crosses with other corn varieties toproduce first generation (F₁) corn hybrid seed and plants with superiorcharacteristics. Still further, this invention is also directed tomethods for producing an inbred maize line MNI1-derived maize plant bycrossing inbred maize line MNI1 with a second maize plant and growingthe progeny seed, and repeating the crossing and growing steps with theinbred maize line MNI 1-derived plant from 0 to 7 times.

As used herein, the term “plant” includes plant cells, plantprotoplasts, plant cell of tissue culture from which corn plants can beregenerated, plant calli, plant clumps, and plant cells that are intactin plants or parts of plants, such as pollen, flowers, kernels, ears,cobs, leaves, husks, stalks, and the like.

The present invention contemplates a corn plant regenerated from atissue culture of an inbred (e.g. MNI1) or hybrid plant of the presentinvention. As used herein, the term “tissue culture” indicates acomposition comprising isolated cells of the same or a different type ora collection of such cells organized into parts of a plant. Exemplarytypes of tissue cultures are protoplasts, calli, plant clumps, and plantcells that can generate tissue culture that are intact in plants orparts of plants, such as embryos, pollen, flowers, leaves, stalks,roots, root tips, anthers, and the like. In a preferred embodiment,tissue culture is embryos, protoplast, meristematic cells, pollen,leaves or anthers. Means for preparing and maintaining plant tissueculture are well known in the art. As well known in the art, tissueculture of corn can be used for the in vitro regeneration of a cornplant. Tissue culture of corn is described in European PatentApplication, Publication No. 160,390, incorporated herein by reference.Corn tissue culture procedures are also described in Green and Rhodes,“Plant Regeneration in Tissue Culture of Maize”, Maize for BiologicalResearch (Plant Molecular Biology Association, Charlottesville, Va.1982), at 367-372. A study by Duncan et al., (1985), “The production ofcallus capable of plant regeneration from immature embryos of numerousZea Mays Genotypes”, Planta, 165 :322-332, indicates that 97 percent ofcultured plants produced calli capable of regenerating plants.Subsequent studies have shown that both inbreds and hybrids produced 91percent regenerable calli that produced plant. Other studies indicatethat non-traditional tissues are capable of producing somaticembryogenesis and plant regeneration. See, e.g., Songstad et al., (1988)“Effect of ACC (1-aminocyclopropane-1-carboxyclic acid), Silver Nitrate& Norbonadiene on Plant Regeneration From Maize Callus Cultures”, PlantCell Reports, 7:262-265; Rao et al., (1986)) “Somatic Embryogenesis inGlume Cultures”, Maize Genetics Cooperative Newsletter, No. 60, pp.64-65; and Conger et al., (1987) “Somatic Embryogenesis From CulturedLeaf Segments of Zea Mays”, Plant Cell Reports, 6:345-347, thedisclosures of which are incorporated herein by reference. Regenerablecultures may be initiated from immature embryos as described in PCTpublication WO 95/06128, the disclosure of which is incorporated hereinby reference.

Thus, another aspect of this invention is to provide for cells whichupon growth and differentiation produce the inbred line MNI1.

The present invention encompasses methods for producing a corn plantcontaining in its genetic material one or more transgenes and thetransgenic corn plant produced by that method.

The molecular techniques allow genetic engineering of the genome ofplants by adding or modifying foreign or endogenous genes (referred tohere as transgenes) in such a manner that the traits of the plant can bemodified in a specific way. Plant transformation involves theconstruction of an expression vector comprising one or more gene undercontrol or operatively linked to a regulatory element (e.g. a promoter).Such vector can be used to provide transformed corn plants, usingtransformation methods as described hereafter to incorporate the gene orthe genes into the genetic material of the corn plant.

To facilitate the identification of transformed plant cells, the vectorof this invention may include plant selectable markers. Selectablemarkers and uses are well known in the art and include enzymes whichprovide for resistance to antibiotics such as gentamycin (Hayford etal., Plant Physiol. 86: 1216 (1988)), hygromycin (Vanden Elzen et al.,Plant Mol. Biol., 5: 299 (1985)), kanamycin (Fraley et al., Proc. Natl.Acad. Sci. U.S.A., 80: 4803 (1983)), and the like. Similarly, enzymesproviding for production of a compound identifiable by colour changesuch as GUS, (beta.-glucuronidase Jefferson, R. A., Plant Mol. Biol.Rep. 5: 387 (1987)), are useful.

Genes included in expression vectors must be driven by a nucleotidesequence comprising a regulatory element, for example, a promoter.Several types of promoters are now well known in the transformationarts, as are other regulatory elements that can be used alone or incombination with promoters.

As used herein “promoter” includes reference to a region of DNA upstreamfrom the start of transcription and involved in recognition and bindingof RNA polymerase and other proteins to initiate transcription. A “plantpromoter” is a promoter capable of initiating transcription in plantcells. “Tissue-specific” promoters initiate transcription only incertain tissues, such as a pollen-specific promoter from Zm13 (Guerreroet al., Mol. Gen. Genet.224: 161-168 (1993). “Inducible” promoter isunder environmental control, such as the inducible promoter from asteroid hormone gene, the transcriptional activity of which is inducedby a glucocorticosteroid hormone (Schena et al., Proc. NatI. Acad. Sci.U.S.A. 88: 0421 (1991)). Tissue-specific and inducible promoters are“non-constitutive” promoters. A “constitutive” promoter is a promoterwhich is active under most environmental conditions such as the 35Spromoter from CaMV (Odell et al., Nature 313: 810-812 (1985) or thepromoters from such genes as rice actin (McElroy et al., Plant Cell 2:163-171 (1990)).

These regulatory sequences will allow the expression of the transgenesin the transformed cells, in the transformed plants. The transgenes maycode for proteins including plant selectable markers but also proteinsadding a value trait to the crop such as agronomic, nutritional ortherapeutic value or proteins conferring resistance to diseases and/orpathogens (e.g. bacterial, fungal, insect or herbicide resistance).

Several techniques, depending on the type of plant or plant cell to betransformed, are available for the introduction of the expressionconstruct containing a DNA sequence encoding an protein of interest intothe target plants. See, for example, Miki et al., “Procedures forIntroducing Foreign DNA into Plants” in Methods in Plant MolecularBiology and Biotechnology, Glick, B. R. and Thompson, J. E. Eds. (CRCPress, Inc., Boca Raton, 1993) pages 67-88. In addition, expressionvectors and in vitro culture methods for plant cell or tissuetransformation and regeneration of plants are available. See, forexample, Gruber et al., “Vectors for Plant Transformation” in Methods inPlant Molecular Biology and Biotechnology, Glick, B. R. and Thompson, J.E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 89-119.

Suitable methods of transforming plant or plant cells, herebyincorporated by reference, include microinjection, electroporation orAgrobacterium mediated transformation; Ti and Ri plasmids ofAgrobacterium tumefaciens and Agrobacterium rhizogenes, (both plantpathogenic soil bacteria), respectively, carry genes responsible forgenetic transformation of the plant. See Gruber et al., supra, Miki etal., supra.

Another applicable method of plant transformation ismicroprojectile-mediated transformation wherein DNA is carried on thesurface of microprojectiles and accelerated to penetrate plant cellwalls and membranes (Sanford, J. C., Physiol Plant 79: 206 (1990), Kleinet al., Biotechnology 6: 559-563 (1988)). In maize, several targettissues can be bombarded with DNA-coated microprojectiles in order toproduce transgenic plants, including, for example, callus (Type I orType II), immature embryos, and meristematic tissue.

Following transformation of maize target tissues, expression of theabove-described selectable marker genes allows for preferentialselection of transformed cells, tissues and/or plants, usingregeneration and selection methods now well known in the art.

The transgenic inbred lines produced by the forgoing methods could thenbe crossed, with another (non-transformed or transformed) inbred line,in order to produce a transgenic hybrid maize plant.

When the term inbred corn plant is used in the context of the presentinvention, this also includes any single gene conversions of thatinbred. The term single gene converted plant as used herein refers tothose corn plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of an inbred are recovered in additionto the single gene transferred into the inbred via the backcrossingtechnique. Backcrossing methods can be used with the present inventionto improve or introduce a characteristic into the inbred. The termbackcrossing as used herein refers to the repeated crossing of a hybridprogeny back to one of the parental corn plants for that inbred. Theparental corn plant which contributes the gene for the desiredcharacteristic is termed the nonrecurrent or donor parent. Thisterminology refers to the fact that the nonrecurrent parent is used onetime in the backcross protocol and therefore does not recur. The donorparent may, or may not be transgenic. The parental corn plant to whichthe gene or genes from the nonrecurrent parent are transferred is knownas the recurrent parent as it is used for several rounds in thebackcrossing protocol (Poehlman & Sleper, 1994, Fehr, 1987). In atypical backcross protocol, the original inbred of interest (recurrentparent) is crossed to a second inbred (nonrecurrent parent) that carriesthe single gene of interest to be transferred. The resulting progenyfrom this cross are then crossed again to the recurrent parent and theprocess is repeated until a corn plant is obtained wherein essentiallyall of the desired morphological and physiological characteristics ofthe recurrent parent are recovered in the converted plant, in additionto the single transferred gene from the nonrecurrent parent.

The selection of a suitable recurrent parent is an important step for asuccessful backcrossing procedure. The goal of a backcross protocol isto alter or substitute a single trait or characteristic in the originalinbred. To accomplish this, a single gene of the recurrent inbred ismodified or substituted with the desired gene from the nonrecurrentparent, while retaining essentially all of the rest of the desiredgenetic, and therefore the desired physiological and morphological,constitution of the original inbred. The choice of the particularnonrecurrent parent will depend on the purpose of the backcross, one ofthe major purposes is to add some commercially desirable, agronomicallyimportant trait to the plant. The exact backcrossing protocol willdepend on the characteristic or trait being altered to determine anappropriate testing protocol. Although backcrossing methods aresimplified when the characteristic being transferred is a dominantallele, a recessive allele may also be transferred. In this instance itmay be necessary to introduce a test of the progeny to determine if thedesired characteristic has been successfully transferred.

Many single gene traits have been identified that are not regularlyselected for in the development of a new inbred but that can be improvedby backcrossing techniques. Single gene traits may or may not betransgenic, examples of these traits include but are not limited to,male sterility, corn endosperm, herbicide resistance, resistance forbacterial, fungal, or viral disease, insect resistance, male fertility,enhanced nutritional quality, industrial usage, yield stability andyield enhancement. These genes are generally inherited through thenucleus. Some known exceptions to this are the genes for male sterility,some of which are inherited cytoplasmically, but still act as singlegene traits. Several of these single gene traits are described in U.S.Pat. Nos. 5,777,196; 5,948,957 and 5,969,212, the disclosures of whichare specifically hereby incorporated by reference.

Industrial Applicability

The seed of inbred maize line MNI1, the plant produced from the inbredseed, the hybrid maize plant produced from the crossing of the inbred,hybrid seed, and various parts of the hybrid maize plant and transgenicversions of the foregoing, can be utilized for human food or livestockfeed. They also may be used as a raw material in industry. The food usesof maize, in addition to human consumption of maize kernels, includeboth products of dry-milling (e.g., meal, flour) and wet-millingindustries (e.g., dextrose, starch).

As livestock feed, maize is primarily used for beef cattle, dairycattle, hogs, and poultry.

Starch Industry now uses maize and maize derived products in variousproductions such as papers, chemistry, and pharmacology. Plant partsother than the grain of maize are also used in industry, e.g. cobs areused for fuel and to make charcoal.

Deposit Information

A deposit of the AgReliant Genetics corn inbred line MNI1 disclosedabove and recited in the appended claims has been made with the AmericanType Culture Collection (ATCC). 10801 University Boulevard, Manassas,Vir. 20110. The date of deposit was Nov. 11, 2003. The deposit of 2,500seeds were taken from the same deposit maintained by AgReliant Geneticssince prior to the filling date of this application. All restrictionsupon the deposit have been removed, and the deposit is intended to meetall of the requirements of 37 C.F.R. §1.801-1.809. The ATCC accessionnumber is PTA-5645. The deposit will be maintained in the depository fora period of 30 years, or 5 years after the last request, or for theeffective life of the patent, whichever is longer, and will be replacedas necessary during that period.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims.

What is claimed is:
 1. An inbred corn seed designated MNI1, wherein a sample of said seed has been deposited under ATCC Accession number PTA-5645.
 2. A corn plant or part thereof, produced by growing the seed of claim
 1. 3. Pollen of the plant of claim
 2. 4. An ovule of the plant of claim
 2. 5. A corn plant, or part thereof, having all the physiological and morphological characteristics of the corn plant of claim
 2. 6. The corn plant of claim 2, wherein said plant is detasseled.
 7. A tissue culture of regenerable cells or protoplasts prepared from the corn plant of claim
 2. 8. The tissue culture of claim 7, wherein the cells or protoplasts are from a tissue selected from the group consisting of meristematic cells, leaves, pollen, embryo, roots, root tip, anthers, silks, flowers, kernels, ears, cobs, husks, and stalks.
 9. A corn plant regenerated from the tissue culture of claim 7, wherein the plant has all the morphological and physiological characteristics of inbred corn plant MNI1, wherein a sample of seed of said inbred corn plant has been deposited under ATCC Accession number PTA-5645.
 10. A corn plant with all the morphological and physiological characteristics of inbred corn plant MNI1, wherein said corn plant is produced from a tissue culture prepared from the corn plant of claim
 5. 11. A method for producing a hybrid corn seed comprising crossing a first inbred parent corn plant with a second inbred parent corn plant and harvesting the resultant hybrid corn seed, wherein said first or second inbred parent corn plant is the corn plant of claim
 2. 12. A method for producing a transgenic corn plant comprising transforming the corn plant of claim 2 with a transgene wherein the transgene confers a characteristic selected from the group consisting of herbicide resistance, insect resistance, resistance to bacterial disease, resistance to fungal disease, resistance to viral disease, and male sterility.
 13. A transgenic corn plant produced by the method of claim
 12. 14. A method of producing a male sterile corn plant comprising transforming the corn plant of claim 2 with a transgene that confers male sterility.
 15. A male sterile corn plant produced by the method of claim
 14. 16. A method of producing a herbicide resistant corn plant comprising transforming the corn plant of claim 2 with a transgene that confers herbicide resistance.
 17. A herbicide resistant corn plant produced by the method of claim
 16. 18. A method of producing an insect resistant corn plant comprising transforming the corn plant of claim 2 with a transgene that confers insect resistance.
 19. An insect resistant corn plant produced by the method of claim
 18. 20. A method of producing a disease resistant corn plant comprising transforming the corn plant of claim 2 with a transgene that confers disease resistance.
 21. A disease resistant corn plant produced by the method of claim
 20. 22. A method of introducing a desired trait into corn inbred line MNI1 comprising: a) crossing MNI1 plants grown from seed deposited under ATCC Accession No. PTA-5645, with plants of another corn line that comprise a desired trait to produce F1 progeny plants, wherein the desired trait is selected from male sterility, herbicide resistance, insect resistance, and resistance to bacterial, fungal or viral disease; (b) selecting F1 progeny plants that have the desired trait to produce selected F1 progeny plants; (c) crossing the selected progeny plants with MNI1 plants to produce backcross progeny plants; (d) selecting for backcross progeny plants that have the desired trait and physiological and morphological characteristics of corn inbred line MNI1 to produce selected backcross progeny plants; and (e) repeating steps (c) and (d) three or more times in succession to produce selected fourth or higher backcross progeny plants that comprise the desired trait and all of the physiological and morphological characteristics of corn inbred line MNI1 listed in Table 1 as determined at the 5% significance level when grown in the same environmental conditions.
 23. A plant produced by the method of claim 20, wherein the plant has the desired trait and all of the physiological and morphological characteristics of corn inbred line MNI1 listed in Table 1 as determined at the 5% significance level when grown in the same environmental conditions. 